Dowel structure for concrete roadways



DOWEL STRUCTURE FIOR CONCRETE ROADWAYS Fldoot. 12, 1935 A gnu lll;

UMTEDS'TATES perature(Hemd` in modern Patented t Mayv 4, 1937 t man - In the..` construction 4of! concrete roadways, the

r same are "divided transversely inta sections with interposedexpansion joints, so that the concrete may expand and contract under changesof'tem-` practice i lmetal bars, termed dowels` are" employed to: maintain the sections in proper alignment. y

` s `:'I'hesef`dowe1s extend across thejoint andthave their ends embedded in the concrete ofthe two with the concrete "while thematerial ofrthe other section moves orslides onn the bar as thesections ,expand or contract; l

, At-Cibviouslyv it is ,in'iportant'4 that these dowels v be properly placed and aligned and thatthey accurately m'aiyntainl *their positions during the castingland settingofthe concrete. It is to this purposelthat linyinveritionis directedlf,

In the old artI various `means wereemployed for` "properly` positioning the dowels` and maintaining theinfin position, such" :for -instance `a"s cross Arods `embedded in the concrete ofi the sections andover which the "endsof the'dowels `were hooked; but athis arrangement `interferes with themovement `of the material ofthe se`c` tions `in expanding andlcontracting, resulting in the stretching and* permanent-elongation of the dowels which tended tcopen the joint;

Another method was 'the' support y of theends ofthe ldowels byameansof stakes' to Vwhich the fdowelswere secured-as by clips; J'Ihis` method may `be satisfactorily used l only g when` thesubbase of theiroadwayis suitable for drivingstakes and it isdifiicultiand time consuming to properly l position and` align the individual dowels. t t In the useof'my invention a plurality` of joint structures includingthe dowels may be setup i `at the side of` the roadwithout interrupting theV concrete castingoperation, and one by one such structures may be set in place as they are re-` In my invention I employ metal chairs which ttthave an intermediate portion upon which the expansion` joint `memberrests and at their ends upwardly extending legs, the legs of the several chairs at veither side being permanently connected by cross barslwhich maintain the chairs in properpositions and relation.A The dowels which t t ,extend through holes in the expansion joint rest 5o on thelcross bars yat either side of the jointand are secured as bywires or clips tothe cross bars The expansion joint member, the dowels and sections, oneendnusuallybeing arranged tobond `roadway between which is interposed the exr i `@represents ,the dowels `which `are preferably diatebase iportion 5 havingadjacentits center 1 frame which may be fabricated atthe factory in the `chairs 'and cross bars `PATENT- "OFFICE f .yaovalza'. f STRUCTURE `'noncouchant l RoAnvvAYs l y t vfllotutisJt. Lind, lii;tslurgflli, `Parli' I t, Appucatjitaoetoberiz, lastsriai No@ 44,714

- Claims @994981,

y concrete cast about the same. l

L'Other novel featuresfof construction, and ar-h 5 rangement of parts will appearl from the fol-` lowing description. y i

In the accompanying drawing, wherein I have illustrated: a practical `embodiment `of theprinciplesbfmy invention, Figtil is aplanview of `l0 the joint lassernblyfwith the joint-member shown in dotted lines.` i i g Figg+2 is an `enlarged section of the jointasfsembly taken on the line'i--Zl in Fig. 1. r

,Figli 3 `1 is a; broken; perspective of the same. l5 Fig. 4 isa viewl similar ,to Fig. 2kbut` with :the concretercast about the assembly. Referring tothe drawing, I yand 42, in Fig.4 4, represent two adjoining sections ofi concrete pansion joint 4member 3 `which may be of any suitable material butwhich is usually formed of asphaltum stiffened with layers` of suitable paper or otherwise reiniorced.-`

. 5 steel barsusually of circular cross section and `which are positioned V,transversely of the joint member t3 and extend through properly placed holes inthe latter. `These holes preferablyrfit the dowels. Y l .i

To hold thedowels in proper positionwand alignment'I `provide for each dowel a chair preferablymade integrally of a metall bar` bent up into fpropershape and comprising` an` intermean expansion part 6 which may be `formed by oifsetting the centeroi the base 5, as best shown .in Figs. '1 and 3, and at each end an upwardly extending leg 'i which rises slightly ,above the i level of the dowels 4. The legs Tof the chairs- 40` "at each side of the expansion joint are xedly Y connected by the metal cross'bars 'which are welded to the legs or otherwise xedly secured thereto, thus forming with the chairs a unitary proper length to suit the road width in view. The elevation of` the Across bars `8 relative tothe legs l" is such that the dowels 4 rest upon thecross bars and against theportions of the legs extending above said cross bars.

The dowelsare wired, as at 9, clipped or otherv wise secured to thel cross bars and legs but in such `a mannerthat in expanding and contracting may move relative to the dowels.

In assembling the joint structure, which may be done prior to putting it in position on the road bed, the joint member 3 is iirst placed in position in the frame resting on the expansion centers 6 of the chairs, as illustrated in 1iig..1,A with the" bars 8 parallel therewith.-v Thef-joint'member 3 is usually protected by the sheet metal cover i open at its bottom and slipped down over the member 3, the cover iii having slots li extending up from its bottom edgesto provide clearance for the dowels 4 when the cover is removed upwardly. The dowels I are then inserted endwise through the holes in the member 3 with their ends resting on the frame as shown, and the dowels are then wired to the legs 1 and bars 8.

The assembled joint member is then placed in.

position in the roadbed and the chairs blocked or otherwise supported. as may be necessary, so that the assembly is properly leveled with the plane of the .dowels substantially parallel with the plane in which the nished road surface is to occupy.

Stakes side of the cover i0 to prevent lateral movement of the joint member during theconcrete casting operation.

The concrete is now cast embedding the joint assembly and the cover i0 is then lifted off.

It is the usual practice to coat the ends of the dowels at one side of the joint with paraillne or some-other substance to prevent bonding with the concrete while the dowels are permitted to bond with the concrete at the other side of the joint. This facilitates the movement of the concrete of the road section relative to the dowels as the concrete expands and contracts.

It is also usual to provide the non-bonding ends of the dowels with slip sleeves i3 whose outer ends are closed and which are only partially Ytelescoped over the ends of the dowels, thereby preventing the dowels from end contact with the concrete when the latter is contracting under low temperatures.

It is evident from the foregoing that the use of my invention greatly facilitates the work of constructing a concrete road, as the joint structures including the joint member, the chairs, cross bars and dowels may be assembled at the side of the road and placed in position as required.

The dowels are properly positioned as the chairs and cross bars may be fabricated as a unitary structure so that the joint member and the dowels will ilt into their proper position when installed in the frame. Again, the structure is i2 are preferably driven in on eithery such that the dowels and the frame retain their proper positions as the concrete is cast and as the latter sets and hardens.

The chairs and cross bars, being permanently cast in the concrete, reenforce the latter and prolong its life and prevent cracking.

The dowels being properly placed and permanently installed, prevent relative vertical or lateral shifting of the sections and thus insure a permanent road surface.

I claim:-

Y 1. A prefabricated frame for supporting the dowels to connect adjacent concrete roadway slabs, comprising a plurality of U-shaped supports, each consisting of an intermediate portion and a leg extending upwardly in a vertical plane from each end of the intermediate portion and parallel to one another, the legs at the corresponding ends of the several supports being disposed in the same planes, and connecting bars rigidly secured to the corresponding legs oi each of the supports at either end of the latter and below the upper extremities of said legs to provide seats for the dowels. v

2. A prefabricated frame for supporting the dowels to connect adjacent iconcrete roadway slabs, comprising a plurality of U-shaped suD- ports, each consisting of an intermediate portion and a leg extending upwardly in a vertical plane from each end of the intermediate portion and parallel to one another, the legs at the corresponding ends of the several supports beingdisposed in the same planes, and connecting bars rigidly secured to the corresponding legs of each of the supports at either end of the latter, said bars intersecting the legs below the upper extremities of the latter to form dowel seats.

3. A prefabricated frame for supporting the dowels to connect adjacent concrete roadway slabs," comprising a plurality of U-shaped supports, each consisting of an intermediate portion and a leg extending upwardly from each end of the intermediate portion and connecting bars rigidly secured to the corresponding legs of each ofthe supports at either end of the latter and at a point below the upper extremities of the legs, the corresponding legs of the several supports being disposed in the same vertical planes and the legs at either end of each support beine disposed ina vertical plane at right angles to the rst mentioned vertical planes, the dowels being supported in the angles formed by the bars and the opposite legs at each of said supports.

Lome J. LIND. 

